The '''Library of Congress''' is the research library
that officially serves the United States Congress
, but which is the ''de facto'' national library
of the United States
. It is the oldest federal cultural institution in the United States. The Library is housed in three buildings on Capitol Hill
in Washington, D.C.
, and also maintains the National Audio-Visual Conservation Center|Packard Campus
in Culpeper, Virginia
, which houses the National Audio-Visual Conservation Center
By 1990, the Library of Congress became the List of largest libraries|world's largest library
, and retains that title today.
The Library's "collections are universal, not limited by subject, format, or national boundary, and include research materials from all parts of the world and in more than 450 languages. Two thirds of the books it acquires each year are in languages other than English."